Discussion
This study shows that patients presenting with R3 retinopathy have higher than predicted levels of social deprivation when compared to controls. This effect is independent of HbA1c level.
It has previously been demonstrated that Type 2 diabetes is more prevalent in deprived populations26–28 which may, in part, explain the increased number of deprived patients presenting with R3 retinopathy. It has also been shown that patients with higher levels of social deprivation are more likely to have worse glycemic control.29,30 This is reflected in an increase in mortality18,31 and an increase in micro vascular complications.30 In this study we found positive association between presence of R3 retinopathy and increased levels of HbA1c (11.5% in R3 patients and 8.4% in controls). However social deprivation was found to be a risk factor for the presentation of the R3 retinopathy, even when glycemic control was adjusted for.
Previous studies have shown that an increase in social deprivation is associated with a decrease in the uptake of screening for diabetic retinopathy32–34 although it has been suggested that this inequality has reduced since the introduction of the national screening program.35 Scanlon et al32 showed that the prevalence of diabetes increased with deprivation quintile, as did the prevalence of sight threatening diabetic retinopathy, whilst the uptake of screening within this patient group was reduced. Our findings are consistent with this study with the additional finding that the effect of socio-economic status is also independent of HbA1c.
Our study shows that once patients had been referred from screening and attended the hospital eye service there was no significant difference in rate of DNA/cancellations or time to laser between the socio-economic groups.
E
thnicity
The link between diabetes and ethnicity is well established. It is believed that 17% of the Asian population living in the UK has been diagnosed with Type 2 diabetes compared to 3% of the White British population.36 Increased levels of diabetic retinopathy in Asian patients were also documented by Raymond et al37 who found that Asian patients living in the Birmingham and Coventry area had an increased risk of sight threatening retinopathy when compared with White Europeans.
In this study we have shown that in our local population Asian patients have an increased risk of presenting late with R3 retinopathy with 44% (n=15) of R3 presentations in our cohort being Asian (vs only 17% [n=11] Asians in the comparator group). It should be noted that this association was no longer present after correction for HbA1c levels, suggesting that this is the primary difference between these ethnic groups.
In addition to this, Asian patients waited longer for their first PRP treatment. This was in part explained by two outliers in the Asian group who had multiple DNAs resulting in delays to laser of over a year whereas no patients in the Caucasian group nor the single African–Caribbean patient had any DNA’s prior to attending their first laser treatment. This high attendance rate suggests that overall there was good engagement regarding the importance of urgent laser. Another factor appeared to be that many more laser treatments were performed on the same day as the first clinic appointment in the White British group. Since we offer this to all patients wherever possible (regardless of ethnicity, IMD status or any other demographic factor) this finding would suggest that in our community there was greater reluctance among the Asian patients to have laser performed on the same day as their first clinic appointment.
These ethnic disparities are commonly attributed to gaps in patient knowledge. Only 37% of ethnic minority patients knew that retinopathy could lead to blindness compared to 63% of the general population.36 This knowledge gap may be associated with language barriers. The 2001 census showed that 60% of people from ethnic minority households in the UK do not speak English as their main language at home.36 It is possible that the seriousness of their condition is not well conveyed through interpreters (perhaps particularly when this is a relative) resulting in non-attendance at retinopathy screening appointments.